Asphalt is a hot mixed mixture of aggregate stone and bitumen. It is used for roads and other paved areas and has now totally replaced tar.
Block paving consists of small rectangular bricks which are usually made out of concrete and are placed on a level sand bed to form the surface.
Sealing paving will bring about considerable benefits but ultimately it is a matter of preference. Many people find that after sealing, the paving will be protected against oil and other stains. Furthermore the fungicides found in the sealant may actually help prevent the growth of unwanted vegetation.
This white residue found on newly-laid paving is called efflorescence. This dust will actually wear off naturally within a couple of months. It will not affect the performance of the paving in any way but if you are concerned about the residue you can clean it off with a specialised brick cleaner. Ask your paving contractor what they would suggest to use as a professional cleaning agent.
Whether or not weeds appear is a good indicator as to the quality of the paving work. Correctly laid paving should prevent the appearance of weeds in the first place. The best method for preventing weeds in your paving is to use weedkiller on the paving from time to time. You can buy weedkiller from any local garden centre. The instructions on the product will offer you preventative measures.
Tackling paving stains will largely depend on the type of stain. Oil stains are some of the most common stain found on paving as paving is frequently used in driveways where motor vehicles are kept. It can very annoying to find that your car has leaked oil onto your new paving. The best thing to do if you find yourself in this situation is to treat the oil stain as soon as possible by using an absorbent powder, such as talcum powder, on the oil stain. You may then choose to use a commercial cleaning agent or some household detergent or emulsifier and a scrubbing brush. Rust stains are also a real headache as they are difficult to get rid of and can change the colour of the paving. The best bet here is to use a household detergent and a wire brush.